Abstract
Purpose :
Boston KPro is currently the most successful artificial cornea. However, the poly(methyl methacrylate) (PMMA)-based stem does not integrate with the donor cornea, serving as potential portal for bacteria. The objective of this research is to enhance biointegration of Boston KPro with cornea using gelatin-based adhesives and polydopamine coating.
Methods :
Poly(methyl methacrylate) (PMMA) discs were first coated with polydopamine (PDA). Uncoated PMMA discs were also used as control. Two types of gelatin-based adhesives were used: dopamine-modified gelatin which is crosslinked by sodium periodate, and unmodified gelatin which is crosslinked by transglutaminase (TG). Each adhesive was applied between two PMMA surfaces (both uncoated and PDA-coated PMMA), and the adhesion force was measured by a mechanical tester. The viscoelastic properties of the hydrogels were measured by a rheometer. Cytotoxicity of these hydrogels was tested on human corneal fibroblasts by alamarBlue assay for two weeks.
Results :
The presence of PDA coating on PMMA significantly increased the adhesion between two surfaces for both adhesives. (8.1 ± 1.8N vs 2.0 ± 0.2N for dopamine-modified gelatin, and 23.1 ± 9.1N vs 1.8 ± 1.2N for unmodified gelatin. P <0.01 for both comparisons.) It is because the quinone groups on PDA coating forms covalent bonds with both unmodified and dopamine-modified gelatin adhesives, whereas only physical binding exists between the adhesives and uncoated PMMA surface. Dopamine-modified gelatin adhered more uniformly and strongly on PDA-coated PMMA compared to unmodified gelatin. However, dopamine-modified gelatin adhesive was weaker than the unmodified gelatin adhesive. Alamarblue assay revealed that there was minimal cytotoxicity to corneal fibroblasts caused by these adhesives.
Conclusions :
Combination of PDA coating and gelatin adhesive significantly increased the adhesion force between two PMMA surfaces because PDA coatings allow the formation of covalent bonds between the gelatin adhesives and the PMMA surface. PDA coating and the gelatin adhesives were non-cytotoxic. This novel method is expected to increase the adhesion between PMMA stem and cornea tissue thereby enhancing biointegration of Boston KPro.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.